Mark Cuban doesn't get emotional on television. Or, at least, he didn't until now.
On Friday's episode of ABC's "Shark Tank," the billionaire investor got choked up — a first, according to the other investors on the show — after hearing 19-year-old start-up founder Tania Speaks pitch her beauty company, Tania Speaks Organic Skincare.
Cuban then offered Speaks $400,000 in return for a 15% stake in her company, which had made $1.4 million in annual revenue at the time of filming, according to Speaks. The deal came with a caveat: Cuban wanted Speaks to teach his two teenage daughters how she built her business.
"I want [my daughters] to meet you, and I want them to learn from you," Cuban said, posing Speaks' mentorship as a contingency. "Maybe you'll even learn something from them."
Speaks said she launched her company in 2017, years after getting bullied over her "bushy, thick and unruly" eyebrows at elementary school recess. She developed an organic growing and styling eyebrow gel, and started selling it in her high school's bathrooms, at trade shows and eventually, on her website.
Now, she also sells cleansers, toners, moisturizers and beard oil — all made with "naturally sourced ingredients," according to her company's website.
Every Shark seemed impressed by the company's financial prowess: After Speaks said she personally pocketed $700,000 the year prior, Daymond John said it was only a matter of time before she was sitting next to the Sharks herself.
Yet finding a deal proved challenging, because none of the Sharks considered Speaks' company a good fit for their respective portfolios. Cuban initially said he wasn't the right advisor for her products, and Lori Greiner said she wanted to see third-party testing to verify the brow gel's ability to maintain and grow eyebrows.
Kevin O'Leary said the 19-year-old's success "humbled" him, but he wouldn't be a qualified "spokesperson" for her skincare business. "I don't think we've ever had anybody in 13 years of Shark Tank stand on that carpet that has achieved what you have," O'Leary said. "But today, I don't think I'm your Shark."
It was only after every Shark declined Speaks' request — $400,000 for 10% of her company — that Cuban decided to reevaluate.
"My wheelhouse is helping guide amazing entrepreneurs like yourself and helping them deal with the legal landmines that come along," Cuban said. "Maybe I can't help with eyebrow [gel]… but I can give you guidance that can help you avoid a lot of the pitfalls."
He offered Speaks $400,000 for 20% of her company, along with the mentorship request for his daughters. Speaks countered with 15%.
Cuban, calling himself "a sucker," agreed. "I saw my daughters — and my son, for that matter — in her," he said. "If I can get her to connect to my kids, that's more important than the money involved."
Leaving the Tank, Speaks said she felt satisfied with the deal and the experience.
"I couldn't have asked for a better outcome," she said. "They even said I would sit there one day and be a Shark. That's the highest compliment I've ever had."
Disclosure: CNBC owns the exclusive off-network cable rights to "Shark Tank."